How Many Kingdoms

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How Many Kingdoms?
Extant
Multicellular Animals
Slime Molds
Archezoans
Archaebacteria
Myxozoans
Protozoans
Bryophytes
True Fungi
Green Algae
Chrysophytes
Tracheophytes
Euglenoids
Brown Algae
Bacteria
Red algae
Extinct
Long Time with Prokaryotes only
Original Cell
2
Animal Features

• Multicellular Eukaryotes
• Heterotrophic Ingestion
• Collagen Protein Connections
• Nerve and Muscle Tissues
• Diplontic (Gametic) Life History
• Gametes Oogamous with Flagellated Sperm
• Zygote to Blastula, perhaps Gastrulation
• Larval metamorphosis into Adult
• Ontogeny Recapitulating Phylogeny

3
Animals

• Domain Eukarya
• Kingdom Animalia
• Phylum Nematoda

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Nematode Body Organization
http//creatures.ifas.ufl.edu/nematode/nem_fig1.jp
g
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Caenorhabditis elegans is a bacteriovorous soil
nematode, feeds on E. coli in vitro, is a genetic
model organism, its genome is sequenced.
N6 XXhermaphrodite XOmale
protandrous
Life cycle 3 days at 20C
vulva
anus
mouth
http//www.esa.int/export/images/Ce_400.jpg
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syngamy
meiosis
protandrous
http//nema.cap.ed.ac.uk/Caenorhabditis/C_elegans_
genome/celeganslifecycle.jpg
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Animals

• Domain Eukarya
• Kingdom Animalia
• Phylum Annelida

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Lumbriculus variegatus California mudworm
This is an aquatic oligochaete annelid Mouth
feeds in sediments Tail extends toward water
surface for gas exchange Body walls nearly
transparent for easy observation For example may
count pulses of blood in dorsal vessel
http//www.westminster.net/faculty/cobler/Lumbricu
lus20variegatus.jpg
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Lumbricus terrestris Canadian nightcrawler or
Earthworm
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The earthworm body is fundamentally segmented.
Here is a typical segment
Each segment is filled with coelomic fluid, under
some pressure, which provides stiffness.
The segments near the head are specialized for
other physiological functions.
http//www.mun.ca/biology/scarr/142003_Annelida.jp
g
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Major Organ Systems in an Earthworm
Reproductive Male Female
Circulatory Gases, Nutrients, Wastes
Excretory
Digestive Food Intake Nutrient Absorption
Muscular Movement
Dermal Gas Exchange
Nervous Sensory and Coordination
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http//myhome.naver.com/c65hoi5/c3/c33236.jpg
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• Characteristics
• More than 100 segments
• Segments separated by partitions that divide
  coelom
• Segments identical except when specialized and
  fused
• Anterior and posterior ends
• Cephalization specialized for burrowing
• Head contains sense organs
• Circular and longitudinal muscles

http//www.student.loretto.org/zoology/phylum_anne
lida.htm
1    Mouth 2    Prostomium 3    Segment 4   
Spermathecal openings 5    Female (oviduct)
opening 6    Male (vas deferens) opening 7   
Sperm groove 8    Papilla 9    Clitellum
(saddle) 10    Paired setae (ventro-lateral)
11    Anus 12    Dorsal surface 13    Ventral
surface  
http//www.student.loretto.org/zoology/Graphic20w
ebs/Earthworm-20external20form.htm
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• Movement
• Setae anchored during movement
• Circular muscles contract
• Hydrostatic pressure increases in anterior
  coelomic cavities
• Body elongates pushing head forward
• Anterior setae grip ground
• Longitudinal muscles contract--posterior pulled
  along
• Coelomic divisions allow simultaneous contraction
  and expansion of segments

http//www.student.loretto.org/zoology/phylum_anne
lida.htm
A    External view B    Section through segment
1    Coelom 2    Circular muscle 3    Cuticle
4    Intestine 5    Dorsal blood vessel 6   
Typhlosole 7    Epidermis 8    Nephridium 9   
Longitudinal muscle 10    Seta 11    Protractor
muscle 12    Retractor muscle 13    Ventral
nerve cord 14    Subneural vessel 15    Ventral
vessel 16    Septum
http//www.student.loretto.org/zoology/Graphic20w
ebs/Earthworm-20muscle20system.htm
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• Nervous
• Sensitive to tough, light, moisture, chemicals,
  temperature, and vibrations
• Light receptors on head and tail--sense direction
  
• Most sense organs and nerves control muscle
  contractions in individual segments
• Pair of ganglia in each segment coordinate
  movement with adjacent segments
• Cerebral ganglion in head controls total body
• Ventral nerve cord connects brain with ganglia

http//www.student.loretto.org/zoology/phylum_anne
lida.htm
1    Anus 2    Intestine 3    Cerebral ganglion
4    Prostomium 5    Mouth 6    Nerve collar
7    Segmental ganglion 8    Pharynx 9   
Esophagus 10    Segmental nerve 11    Crop
12    Gizzard 13    Ventral nerve cord
http//www.student.loretto.org/zoology/Graphic20w
ebs/Earthworm-20digestive20and20nervous20syste
ms.htm
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• Feeding
• Feed on organic matter in soil
• Digest organic matter
• Wastes and undigested soil eliminated as casting
• Loosens and aerates soil
• Digestion
• Soil sucked in by pharynx - esophagus - crop
  (storage) -
• gizzard (grinds soil releasing organic matter) -
  
• intestine (nutrients absorbed)

http//www.student.loretto.org/zoology/phylum_anne
lida.htm
1    Anus 2    Intestine 3    Cerebral ganglion
4    Prostomium 5    Mouth 6    Nerve collar
7    Segmental ganglion 8    Pharynx 9   
Esophagus 10    Segmental nerve 11    Crop
12    Gizzard 13    Ventral nerve cord
http//www.student.loretto.org/zoology/Graphic20w
ebs/Earthworm-20digestive20and20nervous20syste
ms.htm
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• Circulation
• Transport oxygen, nutrients, and wastes
• Flow of blood toward posterior via ventral blood
  vessel
• Flow of blood toward anterior via dorsal blood
  vessel
• 5 pair of aortic arches link vessels near
  anterior
• Smaller vessels branch into segments
• Contraction of ventral vessel and aortic arches
  forces blood through body

http//www.student.loretto.org/zoology/phylum_anne
lida.htm
1    Anus 2    Dorso-subneural vessel 3   
Intestine 4    Dorsal vessel 5    Hearts
(aortic arches) 6    Mouth 7    Ventral vessel
8    Subneural vessel  
http//www.student.loretto.org/zoology/Graphic20w
ebs/Earthworm-20circulatory20system.htm
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• Gas Exchange
• Lack gills or lungs--oxygen and carbon dioxide
  diffuse across skin
• Requires moist skin, thin cuticle, mucus
  secretionlimits habitat!
• Excretion
• Elimination of nitrogen wastes
• Long tubules (nephridia) excrete wastes
• Coelomic fluid enters nephridium through ciliated
  funnel opening
• Some water reabsorbed by blood
• Remaining fluid excreted through ventral pores

http//www.student.loretto.org/zoology/phylum_anne
lida.htm
A    External view B    Excretory system
(nephridium) C-D    Reproductive system C   
Lateral view D    Dorsal view 1    Nephrostome
2    Septum 3    Ciliated tube 4    Bladder
5    Nephridiopore 6    Body wall
http//www.student.loretto.org/zoology/Graphic20w
ebs/Earthworm-20excretory20and20reproductive20
systems.htm
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• Reproduction
• Hermaphrodites--cannot self fertilize
• Worms join head to tail
• Form mucus coat around bodies--each inject sperm
  into mucus
• Sperm move to seminal receptacle
• Eggs move through oviducts to female genital pore
  
• Clitellum secretes mucus and chitinous sheath
• Worm wiggles to slip off sheath
• Eggs and sperm join

A    External view B    Excretory system
(nephridium) C-D    Reproductive system C   
Lateral view D    Dorsal view 1    Nephrostome
2    Septum 3    Ciliated tube 4    Bladder
5    Nephridiopore 6    Body wall 7    Seminal
vesicle 8    Testis 9    Egg sac 10    Male
opening 11    Female opening 12    Oviduct
13    Ovary 14    Sperm duct (vas deferens)
15    Opening to sperm-receiving sac 16   
Sperm-receiving sac (spermatheca)
http//www.student.loretto.org/zoology/phylum_anne
lida.htm
http//www.student.loretto.org/zoology/Graphic20w
ebs/Earthworm-20excretory20and20reproductive20
systems.htm
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http//biog-101-104.bio.cornell.edu/BioG101_104/tu
torials/animals/worm_stuff/worm_ventral.html
http//sps.k12.ar.us/massengale/earthworm_dissecti
on.htm
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Animals probably evolved from a flagellated
protist similar to the choanoflagellates
One step in this evolution is to become colonial.
Here are the choanocytes of one of the simplest
of sponges. Basically the most primitive animals.
Of course the other required step is to eliminate
the chloroplasts of the choanoflagellate
(Chrysophyta!).
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Evolution of Body Organization
Sponge, Cnidarian
Ectoderm Endoderm
Mesoderm
2-layered
3-layered
Acoelomate
Pseudocoelomate
Coelomate
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Development or Evolution?
cleavage
zygote
blastula
2-layered acoelomate body plan
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Platyhelminthes Nematoda Annelida Mollusca Arthrop
oda
Origin of Mesoderm
Echinodermata Hemichordata Chordata
blastocoel
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The Animal Clade
Extant
Chordata
This cladogram omits several smaller animal phyla!
Ancestral Choanoflagellate